Beloved Arc Flash

[zog]

zog,

It is my understanding that there is a Canadian rule that requires this cover and it must be made of the same material as required for the panelboard enclosure. If such a cover would remove the need for PPE when working on the load side of the main breaker, it would be a good idea for our code to require a cover over the line side terminals.
Don

Canada is way ahead of us in arc resisant switchgear and electrical equipment, but changes are coming to address arc rated gear in the next 70E.

However, you cant say there is no need for PPE, even with the line terminals covered, it is the same as operating a breaker with the covers on and for the panel being discussed that would require HRC 0 , which as you know is not the same as no PPE.

 

[don_resqcapt19]

zog,

However, you cant say there is no need for PPE, even with the line terminals covered, it is the same as operating a breaker with the covers on and for the panel being discussed that would require HRC 0 , which as you know is not the same as no PPE.

I keep forgetting about that requirement as my normal work clothes are HRC 2.
I think that such a barrier would be a safety improvement and I will probably submit a 2011 proposal to require it.
Don

 

[jim dungar]

I accept any valid research that show a better way to protect myself, my employees, and my students from injuries as soon as that information is made available to me. Why wouldnt you?

So are you saying that because there will be changes in the next edition of NFPA 70E the 2004 version is now unsafe?

To my knowledge, the issue I addressed concerning Table 130.7(C)(9)(a) Note 3 has only been a problem when it was mis-applied, but it remains as an accepted practice in many company ESWP's.

I expressed my interpretation on NFPA 70E-2004 not what I would do in the OP's place.

 

[zog]

So are you saying that because there will be changes in the next edition of NFPA 70E the 2004 version is now unsafe?

Not at all, i is safer than the 2000 70E, which was safer than the previous edition, etc.. Heck my 1920 NEC says to lick your fingers and touch the conductors to verify they are denergized, it is called evolution, the 2009 70E will be a safer, better, easier to use document that will improve on employee safety just as earlier versions have. Why should I wait for an effective date to improve employee safety?

P.S. You didnt answer my seatbelt question.

 

[jim dungar]

... it is the same as operating a breaker with the covers on ...

If the terminals are barriered how can an arc be created between them, if there is no interaction with them. This is not the same type of issue as a barrier having to contain an arc.

For this theoretical discussion look at 70E-2004 Annex F and then following down the left hand side of the flow chart.

Is there intentional contact... - NO, the basis is no interaction at all.
Is there potential for distrubing... - NO, the basis is no interaction at all
Are approach distances... less.. - NO, the basis is a suitable barrier
Are additional safeguard required... - NO, the basis is a suitable barrier

so, how is this last question answered.
"...does the task involve opening.. or removing... for observation"

If the appropriate PPE is used to open the cover/door and verify the de-energized load side lugs, and there is no attempt to remove the suitable line side barrier - What PPE is required to perform additional work in the panel?

 

[zog]

zog,

I keep forgetting about that requirement as my normal work clothes are HRC 2.
I think that such a barrier would be a safety improvement and I will probably submit a 2011 proposal to require it.
Don

Unless you wear a facesheild all day your normal work clothes are PART of HRC 2. I know that seems like an obvious statement and I know what you meant but I have been to many big companies that had improperly trained thier people that the 8cal coveralls they were wearing was sufficent for HRC 2 protection, they had no idea there was a bunch of other stuff required for HRC 2 tasks.

 

[jim dungar]

You didnt answer my seatbelt question.

I said I had stated an interpretation of an existing standard, not what my actions would be.

 

[zog]

If the terminals are barriered how can an arc be created between them, if there is no interaction with them. This is not the same type of issue as a barrier having to contain an arc.

For this theoretical discussion look at 70E-2004 Annex F and then following down the left hand side of the flow chart.

Is there intentional contact... - NO, the basis is no interaction at all.
Is there potential for distrubing... - NO, the basis is no interaction at all
Are approach distances... less.. - NO, the basis is a suitable barrier
Are additional safeguard required... - NO, the basis is a suitable barrier

so, how is this last question answered.
"...does the task involve opening.. or removing... for observation"

If the appropriate PPE is used to open the cover/door and verify the de-energized load side lugs, and there is no attempt to remove the suitable line side barrier - What PPE is required to perform additional work in the panel?

Annex F or any other Annex are not part of the 70E document, they are supplemtal information. The requirments of the tables still exists, the arc flash hazard still exists if any work is being done in that panel.

 

[zog]

I said I had stated an interpretation of an existing standard, not what my actions would be.

And my question is a valid response to your interpretation, a change is coming, it has been voted on and excepted, so why not embrace it now to save lives.

Besides, go look at the OP again, read it carefully, do you really think the OP knows what fault current is available? Will he apply that exception properly or is he looking for a easy way out. (No offense to the OP, just making a point here)

 

[peter d]

I never thought I would see "beloved" and "arc flash" in the same sentence. Am I the only one who thinks that's funny?

 

[jim dungar]

Annex F or any other Annex are not part of the 70E document, they are supplemtal information. The requirments of the tables still exists, the arc flash hazard still exists if any work is being done in that panel.

I did not state that an Annex was part of the standards. I asked about participating in a theoretical discussion based on the Annex.

Again,
The task table (130.7(C)(9)(a)) seems to have absolutely no gray areas, such as "operation with covers on". However if the task tables are not being used and a study has been conducted to determine the AFIE at this location, what guidance should be given to determine if Article 130 is even applicable when there are no exposed (per the article 100 definition) live parts? I have stated appropriate PPE was worn while 120.1 was being followed and that the guards over the line side terminations are in place.

I have my opinions. I know what my company requires, and I know what I would do irrespective of those requirements.

 

[zog]

Oh there are lots of grey areas in the tables, dont get me started on those.

Back to the question at hand, you open the main breaker and you have this panel cover off nut the (energized) line side terminals are covered with some barrier made of the same stuff the panel is made of right?

If you are using the tables the HRC 0 for operation with the covers on still applies, that is not the same as saying you dont need PPE.

If you did an analysis, you still wear the PPE from the analysis. Arc flash boundaries and PPE requirement apply if the covers are on or off, thats where you seem to be confused.

 

[jim dungar]

If you did an analysis, you still wear the PPE from the analysis. Arc flash boundaries and PPE requirement apply if the covers are on or off, thats where you seem to be confused.

Zog,

I am not confused, in fact I have not even stated my opinion nor what I advise my customers. I have been asking you to join in a discussion on what many people see as a gray area in the standard. By using cogent arguments it becomes easier to convince people to overcome their reluctance to accept a concept.

What NFPA 70E-2004 section, or any other code, are you quoting that says you must wear arc flash PPE when there are no exposed energized parts? If there is no specific code section then what reasoning are you using?

If I extrapolate your previous answer then arc flash PPE must be used around any energized insulated conductor maybe even down to being near SO cord. So why does 70E article 100 contain specific wording defining Exposed (as applied to live parts) and Article 130.7(A) says PPE is required when working only where electrical hazards exist? My discussion was intended to discover why an electrical hazard may or may not exist when there are no exposed live parts due to protective guarding being in place.

 

[billsnuff]

question

question

if i pull the main disco to a panel, the panel is deenergized. but don't i first have to conduct a live-dead-live test to verify that as fact. If so, that requires PPE, unless you use external indicators like Grace phase lites.

 

[zog]

Zog,

I am not confused, in fact I have not even stated my opinion nor what I advise my customers. I have been asking you to join in a discussion on what many people see as a gray area in the standard. By using cogent arguments it becomes easier to convince people to overcome their reluctance to accept a concept.

What NFPA 70E-2004 section, or any other code, are you quoting that says you must wear arc flash PPE when there are no exposed energized parts? If there is no specific code section then what reasoning are you using?

If I extrapolate your previous answer then arc flash PPE must be used around any energized insulated conductor maybe even down to being near SO cord. So why does 70E article 100 contain specific wording defining Exposed (as applied to live parts) and Article 130.7(A) says PPE is required when working only where electrical hazards exist? My discussion was intended to discover why an electrical hazard may or may not exist when there are no exposed live parts due to protective guarding being in place.

The 2004 version dosent specify, but the next version will. The tables list arc flash requirements for tasks with the covers on so it is only "Implied" there. True, the definitions and tables contridict each other and that has led to much confusion.

I have personnaly discussed this topic with several 70E commitee members and have attended panel discussions with the 70E members where this was discussed in an open forum. The "intent" is that the arc flash boundary is to apply whenever a person is "Interacting" with the equipment, that verbage will show up in the next revision.

Additionally I have attended several arc flash tests at KEMA labs in Philly and seen 1st hand how switchgear and panels hold up to arc flash events, never seen a panel contain an arc (Besides arc rated gear tests)

And then there are the dozens of aftermaths I have responded to for actual arc flash events where the gear was destroyed (Some of those pics are posted in another thread).

And most of all one of my best friends was killed a few year back from an arc flash from a 480V MCC that failed, the covers were on that too.

You can sit at your desk and "Interpret" the 2004 70E however you please, I guess we will have to agree to disagree on this until October 2008 when the next 70E is released.

 

[jim dungar]

Billsnuff,
I have already stated the premise that proper procedures and PPE where followed in order to determine that the load side (unguarded) lugs where in an electrically safe condition.

You can sit at your desk and "Interpret" the 2004 70E however you please, I guess we will have to agree to disagree on this until October 2008 when the next 70E is released.

Zog,
I have never said it is my job to offer official interpretation of NFPA 70E. I simply began the discussion based on the fact that 110.7 (F) requires you to identify the risk and says that Annex F is one method.

I am not talking about operating the disconnect without PPE, I am not asking if the line side barriers can contain an arc (which they will not do).

I am aware of the upcoming phrase "interacting with the equipment". I am asking if these line side barriers prevent you from "interacting" with energized equipment if the disconnect has been locked off following correct procedures.

In a related "interacting" issue, during one "disconnect" enclosure test cotton is packed around the enclosure while the device is subjected to a fault. In order to pass the test and be rated for that fault current the cotton must not ignite, which infers that the resulting arc is contained within the enclosure. Given this test, what hazard exists when operating this disconnect within its listing (of course any HRC decision requires the switch be applied within its ratings)?

You may have strong opinions for your PPE recommendations but the law is NFPA 70E (as applied by OSHA) and companies need to decides how to address these "gray areas" in their safe work practices program.

 

[zog]

Lets not go changing what was asked and said, you began the discussion by argueing with my advice to the OP that he not use the "reduce by 1 HRC" exception because the next revision had not gone into effect yey, even though you know the changes are coming and therefore substational evidence exists that reducing the HRC can lead to burn injuries. You keep changing the discussion and nitpicking my posts while ignoring the valid points and questions.

You never answered my seatbelt question because you and I both know what the answer is and how relevant that question is to our whole disagreement.

P.S. I have no idea what you are asking regarding this cotton packed around a disconnect test, what ASTM is that based on. I need to look that one up, I need to know how 2nd degree burns (1.2cal/cm2) and cotton ignition (5 cal/cm2) relate.

 

[jim dungar]

Lets not go changing what was asked and said, you began the discussion by argueing with my advice to the OP that he not use the "reduce by 1 HRC" exception because the next revision had not gone into effect yey, even though you know the changes are coming and therefore substational evidence exists that reducing the HRC can lead to burn injuries. You keep changing the discussion and nitpicking my posts while ignoring the valid points and questions.

You never answered my seatbelt question because you and I both know what the answer is and how relevant that question is to our whole disagreement.

P.S. I have no idea what you are asking regarding this cotton packed around a disconnect test, what ASTM is that based on. I need to look that one up, I need to know how 2nd degree burns (1.2cal/cm2) and cotton ignition (5 cal/cm2) relate.

I never argued against your advice, though I did question when new standards should be applied. In fact I did say that if you were going to use the new standard then even my original answer for labels could be wrong.

I keep wanting to discuss common questions that people often ask as they are creating their ESWP programs. I started with a possible way decide if an area is safe, and then added what is meant by "interaction" in the new standard.

You keep asking if I would implement new actions that I know to be safer than my current actions. I have stated that I want to stay away from my purely personal opinions, as they do not apply to the grey areas of the standard.

As far as second degree burns go, without a full analysis of the values, if Table 130.7(C)(11) allows flammable cotton to protect you to HRC=0 then my suggested test may have some validity.

I do know of at least one manufacturer that does say operation of some of their UL Listed enclosed devices never presents more than a hazard risk of 0 as long as they are applied within their short circuit rating. Can an argument against them be supported?

 

[zog]

As far as second degree burns go, without a full analysis of the values, if Table 130.7(C)(11) allows flammable cotton to protect you to HRC=0 then my suggested test may have some validity.

Cotton ignites around 5 cal/cm2, 1.2 cal/cm2 causes 2nd degree burns, there is a big gap there. Have you seen a 2nd degree burn? My daughter got 2nd degree burns when she was 18 mos old and for 3 months 3 times a day we had to soak her burns in the tub and scrub them with a brillo pad, the screamed every time, longest 3 months of my life (She is fine now).

So your test in theory would allow no protetion (Or HRC 0, I am not clear on what you are saying thee) if the cotton did not ignite? If so then a Ei of <5cal/cm2 is possible without PPE requirements. Have you ever seen a 4cal/cm2 arc flash? If not I can send you a video of one, I promise it is alot worse than you would expect if you have never seen one. Doing arc flash studies with Ei's at 30. 40. even 100+ cal/cm2 , 4 seems like nothing, but that is a horrible assumption to make.

I do know of at least one manufacturer that does say operation of some of their UL Listed enclosed devices never presents more than a hazard risk of 0 as long as they are applied within their short circuit rating. Can an argument against them be supported?

No, not if they have test data to back that up, which I would assume they do. The (here we go again) 2009 70E will account for this (Arc resistant switchgear) in the HRC tables, I think all of the 600V and less stuff was HRC 0, maybe there was some HRC 1, I would have to check that.

 

[jim dungar]

No, not if they have test data to back that up, which I would assume they do. The (here we go again) 2009 70E will account for this (Arc resistant switchgear) in the HRC tables, I think all of the 600V and less stuff was HRC 0, maybe there was some HRC 1, I would have to check that.

The manufacturer is not talking about arc resistant switchgear. They mean the operation of their fusible switches and circuit breakers and drawout circuit breakers that they offer now.

What test method is acceptable per NFPA 70E? 70E-2004 Table 130.7(C)(11) considers non-melting flammable material and untreated cotton clothing as adequate protection for a hazrd risk category of 0.

How should companies write their ESWP's to address the vague verb "interact"? Going back to my original point of discussion, why doesn't a barrier which prevents contact with the energized line side terminations of a locked open switch also prevent interaction with them?